In the characteristic test for, for example, mobile communication terminals, a signal generating device has been used in order to supply a test signal to the mobile communication terminal. In general, the signal generating device includes an analog circuit. The analog circuit has frequency characteristics and the output level of the signal generating device varies depending on the frequency. Therefore, it is necessary to correct the frequency characteristics of the output level of the signal generating device.
For example, Patent Document 1 discloses a correction circuit as a circuit to carry out this type of correction. The correction circuit disclosed in Patent Document 1 includes an attenuator which attenuates an output signal from the signal generating device, a memory which stores, as a table, correction data for the frequency characteristics of the signal generating device which are measured in advance, and a CPU that reads the correction data from the memory and sets the amount of attenuation of the attenuator. The correction circuit corrects the frequency characteristics of the output level of the signal generating device.